Micrometer caliper



Feb- 24 1948* R. A. WILKINSON MICROMETER CALIPERS Filed Nov. 14,v 1945 EEAEEAQEEE. E55@ 5. EE. Ela..

FLE.

Patented Feb. Z4, 1948 uNlTE-D.. STATES PATENT ovl-Fics i 2Av Claims.

The invention relates tolmicrometer calipers,

for the use of machinists and draftsmen, having for an object to provide an improved device of this description adapted to give simultaneous readings in thousandths of an inch as well as in inches and thus save time. Another object is to provide such a device adapted for use to.. give readings in inches only.' Other objects and advantages will appear hereinafter or will', be. obvious.

The invention consists inthe novel construction and combinations of parts as hereinafter set forth in the claims.

In the accompanying drawings,

Figure 1 is a front View of the calipers, designed for inside readings.

Figure 2 is an edge view of the same.

Figure 3 is a view similar to Fig. 1, of the calipers as designed for outside readings, the dials being removed.

Figure 4 is a detail side view of one leg of the calipers.

Figure 4a is a detail edge view of the same.

Figure 5 is a detail edge view of.the other leg.

Figure 5a is a detail side view of the same.

Figure 6 is a detail side View of the pivot pin.

Figure 6a is a detail end view of the same.

Figure 7 is a detail fragmentary side view of the dial case, partly in section, showing the thousandths dial and the manipulable means for disengaging the pinion.

Figure 8 is a detail side view of said manipulable means on a larger scale.

Figure 9 is a detail fragmentary face view of the inches dial, showing the thousandths dial and its brake springs.

In these drawings, the numeral I designates the legs of the calipers, having a pivotal connection, one of said legs having two parallel spaced hollow cylindrical hub projections 3, within which fits a single hollow cylindrical hub projection 4 of the other leg. a pivot pin 5 being fast to the projection li, within the perforation thereof to move with said leg and engaging the perforations of the projections 3, saidA pin having a central longitudinal axial perforation 6, Within which is secured a drive shaft 1 to move with said pin, as

. the calipers are opened or closed in taking read ings.

A circular case 8 is spaced laterally of said legs, with its center located centrally of said legs, the outer face of said case forming the inches dial 9. An anchor I0 for said case is secured to one of said legs to hold the case stationary with respect to said leg.

The drive. shaft 'I is providedwith a spur gear wheel. I I', meshing with a pinion I2, the shaft of which pinion has` aninches hand I3 fast thereto. A thousandths dial. I5 is locatedwithin the inches dialand is separate` therefromfor separate ma'- nipulation purposes as will be explained. A second pinion I6 has a gear train connection Il with the shaft of said rst named pinion, a thousandths hand IBS being secured to the shaft of saidsecond pinion.

Manipulable means are provided for shifting said secondv pinion I6 out of and into mesh with said gear train, during such manipulation and thereafter, said means comprising a shifting lever I9, fulcrumed at 20, and engaging at its forked upper end with a throwout collar 22, to accomplishfthe shifting, a push and pull pin 23 having bearings in a lateral wall of said case and b-eing provided with spaced seats 24 within one or the other of which a spring-pressed ball 25 of the case engages to hold the lever as shifted with said pinion in mesh with the gear train or released therefrom.

Simultaneous readings may be taken in inches and thousandths of an inch, or other fractions of an inch than thousandths; or readings may be taken in inches only upon shifting said second pinion out of mesh with said gear train.

The thousandths dial has an arcuate portion thereof projecting without the circumferential edge wall of said case, for convenient use in manipulation, after the said second pinion has been shifted out of mesh with said gear train, in setting the calipers prior to use, in taking inch dimensions only, as aforesaid, or in resetting the hands to zero, the latter being prior to such shifting. Hair springs (not shown) are used to take up slack in the gears and to take up slack in the hand of the inches dial, so that there shall be no lost motion. Brake springs 2li are provided for the thousandths dial so that it shall not work too freely. This thousandths dial is secured by suitable means (not shown) to the inches dial face plate so that it shall be capable of being rotated.

The drive shaft 'l being secured centrally of the pivot pin 5 as aforesaid provides for more accurate readings, inasmuch as it is of small cross sectional area and the movement of rotation thereof in opening and closing the calipers is comparatively slight, thereby reducing liability of error. This location also does away with need for more elaborate or complicated means for communicating the movement of the legs of the calipers in taking readings to the dial hand or hands, and also provides for location of the circular dial case centrally with respect to said legs for a, balanced construction. The pivotal or hub construction aforesaid is designed to reduce lost motion to a minimum.

I claim:

1. A micrometer calipers, having two legs provided with a pivot pin connection, said pin being fast to one of said legs to move therewith and having a longitudinal axial perforation, a drive shaft secured within said perforation to move with said pin, an inches dial, a gear upon said drive shaft, a pinion meshing with said gear, an

inches hand upon the shaft of said pinion, a thousandths dial located within said inches dial and separate therefrom, a second pinion having a gear train connection with the shaft of said rst named pinion, a thousandths hand upon the shaft of said second pinion,` said thousandths dial having an arcuate portion .thereof projecting without the circumference of said inches dial for manipulation purposes, manipulable means for shifting said second pinion out of mesh with said gear train during such manipulation, said inches dial being spaced laterally of said legs, and an anchor for said inches dial fast to one of said legs.

2. A micrometer calipers, having two legs provided with a pivot pin connection, said pin being drive shaft, a pinion meshing with said gear, an inches hand upon the shaft of said pinion, a thousandths dial located Within said inches dial and separate therefrom, a second pinion having a gear train connection with the shaft of said rlrst named pinion, a thousandths hand upon the shaft of said second pinion, said thousandths dial having an arcuate portion thereof projecting without the circumference of said inches dial for manipulation purposes, manipulable means for shifting said second pinion out of mesh with said gear train during such manipulation, a circular case the outer face'of which forms said inches dial, said case being spaced laterally of said legs, said gear, said gear train, both pinions, and said manipulable means being located within said case, and an anchor for said case fast to one of said legs,

ROBERT A. WILKINSON.

REFERENCES CITED The following references are of record in the filek of this patent:

UNITED STATES PATENTS Number Name Date 673,944 Doty May 14, 1901 686,455 Hill Nov. 12, 1901 1,219,149 Puglisi Mar. 13, 1917 FOREIGN PATENTS Number Country Date 94,716 Germany 1897 

